TIJUANA, Mexico - A busy public hospital that serves the city's poorest residents was the scene of a shootout Wednesday that claimed the lives of two law-enforcement officers and left hundreds of frightened patients and staff members locked inside for several hours as police searched for suspects.

As soldiers and police swarmed the area in the city's Rio Zone, the 120-bed General Hospital was partly evacuated shortly after noon, with some patients temporarily moved to a city park across the street and treated on cots set up on a basketball court. Others were driven to nearby hospitals.

Sixty patients were evacuated, according to Baja California health authorities, but it remained unclear Wednesday how many were left inside.

The incident at the hospital caused a commotion that was rare even for a city plagued by drug-related violence. It began about 10:30 a.m., a couple of miles from the hospital, near the city's bus station, known as La Central Camionera.

By late afternoon, two suspects were in custody and another was dead, and the hospital was again admitting patients and visitors. But numerous questions persisted about the attack in the parking lot of the hospital and the emergency room area.

"Definitely we're talking about organized crime," said Jaime Niebla, a top investigator with the Baja California Attorney General's Office.

MEXBATTLE - A federal police officer pointed his gun at a suspect in custody inside a patrol truck in Tijuana. A federal organized crime unit has taken charge of the investigation into the shootings. Photo by John Gibbins.

MEXBATTLE - An ambulance that was riddled with bullet holes sat at the entrance to the emergency room of the General Hospital in Tijuana. Photo by John Gibbins.

MEXBATTLE - A woman was carried from the emergency room at the General Hospital in Tijuana. Photo by John Gibbins.

State and federal officers on patrol had been chasing two armed men who were in a white pickup in a residential neighborhood behind the bus station. The suspects refused an order to stop, shot at the officers, then ran when their vehicle crashed into a bus, according to the Baja California Attorney General's Office. One of the suspects was injured, and another who apparently had been shot fell dead in the concrete channel of the Tijuana River.

As a Red Cross ambulance carried the wounded suspect and an injured bystander to General Hospital, armed assailants were in pursuit.

State investigators said the assailants were trying to free the injured suspect as they shot their way through the parking lot and into the hospital's emergency room. Two state police agents who were at the hospital on unrelated matters were killed. They are Jose Adrian Lopez Torres, a member of the State Preventive Police, and Rodolfo Garcia Parrales, a state prison guard.

A federal organized crime unit has taken charge of the investigation, according to a statement released late Wednesday by the Baja California Attorney General's Office. Among the items seized are three guns, three ski masks, and a bullet-resistant vest.

Hours after the men entered the hospital, signs of the battle were evident. Bullet holes pocked the glass door of the emergency room. Bullets had pierced a nearby ambulance and the metallic roof that covered an outdoor waiting area and chipped a wall and some concrete benches.

Inocencia Lopez, 27, was in the first floor maternity ward after giving birth to her fourth child at 8:30 a.m. when she heard shots, she said.

"Someone came in to say there had been injuries, and then they closed the doors because we could hear a great commotion," she said.

Meanwhile, her husband was outside in the emergency room waiting area, watching as the assailants fired their weapons and burst into the hospital. Jose de Solano said he saw four or five attackers and ran inside after them to find his wife. "I wanted to get to where she was, but I couldn't because there were too many people running in every direction."

About two hours after the initial assault, gunfire resounded from inside the hospital, sending bystanders outside once again scurrying for cover. Law enforcement authorities had yet to clear up questions Wednesday night about the origin of that gunfire.

Jose Bustamante Moreno, Baja California's secretary of health, reported that part of the hospital had been flooded, apparently because a pipe had burst. In a statement late Wednesday, the health department said the hospital would mostly be operating as usual today, and crews were working to repair the damage, which was affecting the blood bank and surgery area. Until the repairs are complete, emergency cases are being rerouted to other hospitals, the statement said.

Patients without any kind of insurance are treated at the hospital, which means many patients are those who work in the large informal sector of the Mexican economy. Those people are not on social security rolls and therefore do not qualify for treatment at social security hospitals.

Shortly after taking office late last year, Mexican President Felipe Calderon started a series of operations against organized crime in several states. Operation Tijuana, which also has been called Operation Baja California, started Jan. 2 with 3,300 soldiers and federal agents sent to the border region.